13 ms·
Balcony solar panels – one-year results
- irrational 5y agoSide question, I've been thinking about adding on above my garage. One side of the new roof would face S-SW (currently the roof of our house only faces east and west). How would I figure out the optimal angle to build the roof for my latitude so that solar panels would get the maximum exposure?
- bityard 5y agoThe optimal angle is perpendicular to the sun at all times. Which changes throughout the day, and also throughout the year. My recommendation would be to let the structural, material, and economic factors determine the pitch of the roof, and let the installers determine the optimal angle of the solar panels.
- LeifCarrotson 5y agoMathematically, you want to be perpendicular to the sun, so typically you'd take your latitude and set that as the angle to horizontal. Some systems allow you to adjust the angle seasonally, angling down to latitude+23 degrees for the middle of winter and up to latitude-23 for the middle of summer, but your roof probably doesn't support that. Also, you might want to bias a little towards the sky rather than the ground; on cloudy days the light comes from all over the sky (less comes from the low-albedo dirt), and if it's fixed year round, again bias it a little towards summer angles because there's less solar energy and more clouds in the winter. Realistically, though, the angle just doesn't matter that much. More silicon area covers a multitude of inefficiencies. You're already proving this by setting a constant azimuth of S-SW because that's where the house aims, doing that again with the angle of elevation isn't that bad. A conversation with a roofer/contractor might go something like this: "Not sure what this nonsense about the arctangent of the latitude is, but you want a slope of 13 7/8 in 12?!?! That's ridiculous, I don't know if I could even get a permit for that, much less trusses or shingles. I did hear of a guy who did something like that for a custom house, he's probably booked out for 20 months and I hear he charges $900/square, talk to him not me if you really, really want that. I can do 9/12 pitch [36.87 degrees] at $600 per square [hundred square feet]. If you go down to 6/12 [26.57 degrees] my guys can walk it and get the job done faster, I'd go $550/square, final offer." Just match existing architecture and reinvest the savings in more panels. Here's an excellent article with some links to papers and calculators: https://www.thesolarnerd.com/blog/optimal-solar-panel-tilt-most-calculators-are-wrong/ https://www.thesolarnerd.com/blog/optimal-solar-panel-tilt-m...
- dmitrygr 5y agoCannot read article because medium demands sign in and an account
- notJim 5y agoAre there any safety or other technical issues with a setup like this? I am comfortable with small-scale solar setups because I've built one for a van, but I had no idea you could build a simple grid tied system like this. Is the inverter really just plugged into a wall outlet? If it's this simple, I might just throw together a system with some spare panels in my garage.
- tootie 5y agoIs it at all practical to just run DC power lines through your house? Would that save some efficiency lost during transforming knowing that will end up as DC in a lot of household appliances?
- rightbyte 5y agoThe contactors need to be much stronger to break a DC current compared to AC. The appliances would be quite expensive.
- SavantIdiot 5y agoOne problem is the DC voltage requirement is different for every device. Look at the wall-warts in your house. I have in my lab: 24V, 19V, 17V, 12V, 5V, 3.3V. Yeesh. If you delivered 48VDC you'd still need a DC SMPS at each point, but an SMPS is way more efficient than a transformer.
- cadr 5y agoHow are you comparing the efficiency of a SMPS and a transformer? They are different things. Would love to hear more.
- Dylan16807 5y agoYou look at the percentage, such as 95%? I'm not sure what you're asking. Add up the losses in each conversion, plus the losses from the house wiring.
- MisterTea 5y agoMost AC power distribution transformers are 95% or better. As of 2016 the US EPA mandated even greater efficiency of 97% or greater: https://www.ecfr.gov/current/title-10/chapter-II/subchapter-D/part-431#subject-group-ECFRf791a7b3e315557 https://www.ecfr.gov/current/title-10/chapter-II/subchapter-...
- saalweachter 5y agoEvery time I look into this the conclusion I end up with is "not enough things are produced using 24V/48V DC to be worthwhile". It seems like you could replace a certain fraction of room wiring with PoE from an energy budget point of view -- lights, lamps, chargers and other doodads don't need to draw more than a few watts each, so you could get by with just an outlet or two per room for large power draws everywhere but the kitchen, and PoE for all the rest. But the world just isn't built for it.
- SavantIdiot 5y agoCan you just start pumping current into the transformer on the pole outside your house, just like that? Even if the meter doesn't "spin backwards", is that safe to do? (Not considering the other top-level comment about the grid going out, just general delivery.)
- Nextgrid 5y agoTransformers work both ways so I personally don't see a problem, but even if they didn't, you'd have to have a lot of panels before you will be running the transformer "backwards" as you'd have to first power all the others users of that transformer.
- deleted 5y ago[deleted]
- deleted 5y ago[deleted]
- dn3500 5y agoFrom an electrical standpoint it's safe as long as your inverter cuts off when grid power goes out. Grid tie inverters are designed to do that. Some meters will be unhappy running backwards. They may not register the right numbers but they won't blow up. From a regulatory standpoint your utility won't be happy with you feeding power to the grid if you haven't notified them ahead of time. How unsafe that is depends on your local laws. The dangers here are fines and service cutoffs, not fires and electrocution.
- ortusdux 5y agoTech Ingredients on YouTube reciently did some videos about increasing small scale solar efficiency by adding DIY reflector panels. Overview: https://www.youtube.com/watch?v=FKhszB4E1_M https://www.youtube.com/watch?v=FKhszB4E1_M Build instructions: https://www.youtube.com/watch?v=knlQFlxCwrs https://www.youtube.com/watch?v=knlQFlxCwrs
- ortusdux 5y agoI re-run the numbers every year, but solar just does not make fiscal sense for my house. For 2022, my utility lowered the our set rate from 6.98 cents/kWh to 6.5, which puts me at about half the national average.
- krallja 5y agoDo you live adjacent to a hydro dam or solar farm, or what’s the reason for such a low price?
- barbacoa 5y agoIf you live near fracking Wells they have byproduct natural gas that is basically throw away cheap since it's difficult to transport without those unpopular pipelines.
- emilecantin 5y agoIn Québec we have similar prices throughout the province. "We" massively invested in hydro power back in the 60s-70s, and it's paying off very nicely. What's funny is that everyone still complains about their Hydro bill, but that's because virtually every house is heated with electricity (baseboard heaters), and we have a pretty cold climate. For example, yesterday my house consumed ~180kWh and the outside temperature peaked down to -20°C. EDIT: mistyped a number
- jandrese 5y agoYeah, if you happen to live near hydroelectric capable rivers then it's one of the best forms of green energy possible. In fact it is so good that most places where it makes sense have already been installed.
- emilecantin 5y agoMost of them are not very close at all, but "we" also invested in long-distance transport at 735 kV (among the highest voltages in use at the time), which reduces losses. A good chunk of it came down in the late 1990s due to a freezing rain storm, plunging half of Québec in the dark, but ut was rebuilt pretty quickly.
- jack_riminton 5y agoIt'd be interesting to see what the payback would be like with a small-scale battery system. Obviously it'd be a lot longer and more suited to places with common outages but interesting nonetheless
- Syonyk 5y ago"Never. By a long shot." At least in terms of financial outcomes. If it improves reliability, it's common enough, but a solar + battery system does well to come in at 4-5x grid rates, even in expensive areas. My office system (off-grid solar + battery) has now dropped below $1/kWh delivered... but not by much. And the batteries are more than halfway through their expected service life (10 years, flooded lead acid). I do it because it's interesting to learn and experiment with, and because trenching power out here would suck, but I don't pretend it's cheap. On the other hand, it is more reliable than the power grid...
- turtlebits 5y agoAdding battery storage is prohibitively expensive- not worth it unless you're preparing for an emergency or need to go off grid.
- jandrese 5y agoBatteries are getting cheaper every day (well, not so much lately), but if your grid is reasonably stable and your power company does net metering they just don't buy you very much. If you live in an area where the power is regularly going out (or are off grid entirely) then they give you a whole home UPS which is nice, but it doesn't save you money. The only other major use case is when your local power company is run by unrepentant assholes and they screw you over on excess production so it makes sense to try to save that excess production instead of feeding it back to the grid. But this is a penalty reduction instead of an actual savings.
- david422 5y agoI just got solar panels. I was crunching the numbers and it's a long payback. I am really waiting to see how it turns out. Currently, the days are very short - 9 hours of sunlight. It's been cloudy and/or snowy quite a few days - which means zero production. Partly cloudy also drops production significantly. On a good day we might generate 25-30kWh of electricity. But that is also approximately what we use. I'm hoping that during different seasons we will have higher production and/or more days of the week generating. Because otherwise, our electric bill every month is not a huge part of our expenditures, and we've paid a large upfront cost to (currently) only reduce that by a portion.
- spockz 5y agoFor us the payback is about 3.5-4 years depending on how much I use myself and how much I sell back on the grid. Granted, I got the panels at a discount.
- dabeeeenster 5y agoI got a 2.4kw array on my smallish roof in London. I was tracking payback at ~24 years but all of a sudden I'm paying 25p/kwh instead of 12p/kwh, which means my payback is considerably shorter!
- stinos 5y agoYup. I did a very quick calculation based on last years yield and if the new energy prizes remain at this level it seems our 2.7kWp is going to pay itself back in about 4 years (!) instead of about 9-10 years. Crazy.
- jandrese 5y agoYou might have spent too much on the array. Most people target a 10-15 year payback period. But benchmarking it on December/January production is also likely to blow up your projections as you noted. If you're net zero in the middle of winter you're probably going to be positive in the summer unless you live in a very hot climate. IMHO sizing an array to be net positive over the course of a year is probably a mistake, as this draws the ire of your power company and they'll probably screw you on overproduction. If you're planning to buy an electric car or something in the near future then it might not be a problem, but generally the best plan is to buy for about 100% of your total yearly usage. Solar panel production typically decreases by 2% during the first year of operation (0.5% every subsequent year) so you'll be slightly net negative which keeps you on good terms with the power company. One nice thing with the panels is that they effectively lock in your power rate at whatever you paid. You won't get burned by ever increasing power rates. It's a hedge against future rate hikes.
- elric 5y ago> The last thing which is important to know is how we can send the electricity to the grid. It is simple from a technical point of view [..] It's not simple from a technical point of view. It's bewilderingly complex, in fact. If not done right, it can threaten the stability of the grid. It requires parts of the grid to have increased capacity. In/out balance needs to be maintained at all times. Decentralized production is great, but it could really benefit from more decentralized storage. Might be useful to start installing sizeable batteries near all medium->low voltage substations. Seems like the right place for it.
- aerojoe23 5y agoAlso he didn't mention an auto disconnect if the power goes out, and as I understand it this is required in most places. You could be responsible for killing someone with out it. The power is out and the lines are being worked on. The line is supposed to be dead. Your solar system is making power and sends it out of the house, back on the grid.
- avianlyric 5y agoHe did. He’s using a grid tie inverter which requires the grid to provide a synchronisation signal for the output AC waveform. No power, no grid signal, no output AC waveform.
- jandrese 5y agoThis is a standard feature of every grid tie inverter. Unfortunately it also means you can't power your house when the grid is out unless you also have a battery attached. Not that you would want to run appliances with the power dipping out randomly anyway. Maybe to charge a laptop/phone or run basic incandescent bulb/electric space heater/toaster type loads.
- llampx 5y agoAs the author mentioned, that can be done with a DC-DC converter.
- stormbrew 5y agoI really hope at some point we can stop having every conversation about renewable and electrifying tech be about "payback". Especially among people who can afford to take some loss on it for the greater good (ie. much of the HN demographic). There are benefits besides money from removing your dependencies on fossil fuels. The fact that it's even in the ballpark of breaking even is a very nice side effect, but it's not the point.
- jonnycomputer 5y agoIn rural, very red California, solar is installed everywhere. I doubt its being done because of climate change, or "for the environment". Its the payback.
- stormbrew 5y agoI'm not sure why you think I said anything that contradicts this.
- jabroni_salad 5y agoPersonal electricity generation can be surprisingly diverse. You have hippie homesteaders, catastrophe bunker preppers, libertarians who just want to be off grid because they want to, etc. Environmentalists are just one of many groups that solar sellers are targeting. Also, if you are extremely remote, getting the grid built out to you might cost tens of thousands, to the point that the up-front costs of nongrid power are even more palatable.
- hnburnsy 5y agoCould unreliability from their power provider be a bigger factor? No one wants to suffer rotating blackouts and have their freezer food spoil or miss meetings when working from home.
- SubiculumCode 5y agoEveryone seems convinced Californian's are all suffering from blackouts all the time. I'm in Sac area, and I've only experienced one in the last three years, and it was just a few hours.
- 71a54xd 5y agoUsing excess energy to heat a thermal mass is infinitely better for the person who owns the solar panels / efficiency than piping it back into the grid, where you a) need more electrical work (paying an electrician to install a grid-tie inverter costs thousands and also negates your ability to use the power off-grid if you ever wanted to add batteries) and b) best case get credits that are deliberately priced next to nothing. The price of LifePo4 lithium batteries has also plummeted in recent years. Cool project though!
- frankus 5y agoYou're both overgeneralizing and overstating the case here. PV is superior to solar thermal in a number of important ways, and grid-tie systems can be extremely cost-effective relative to storage. The article here https://www.greenbuildingadvisor.com/article/solar-thermal-is-really-really-dead https://www.greenbuildingadvisor.com/article/solar-thermal-i... details them, but the TL;DR is that solar thermal is only useful for when a) the sun has been shining for the last few hours and b) your household currently can use a source of (low-grade) heat. In contrast, PV can be used for all sorts of things (transportation, cooling) and can be exported to your neighbors via the electric grid. Thermal storage is also not especially space-efficient. Best-case scenario is that you can store about 100 Wh (~US 1¢) of energy per kilogram of mass, which pretty much rules out any kind of seasonal storage. Also grid-tie systems are a phenomenal deal compared to battery storage. I live in a place with a pretty favorable regulatory environment, but the net effect of my grid-tie system is that I get to rent an 8 megawatt-hour battery for around US$8 per month. A battery system like that would likely cost in the single-digit millions if I were to purchase it.
- sacred_numbers 5y agoI think the person you are replying to is suggesting using PV panels to heat a thermal mass (using resistive heating or possibly a DC heat pump) to avoid the expense of an inverter and other electronics necessary to connect to the grid. This is actually a pretty good idea now that PV panels are a much smaller percentage of the total cost of solar nowadays.
- JTbane 5y agoAre solar panels worth it if you live at higher latitudes? I'd like to see a comparison between New England, NYC and Arizona in terms of how fast they go net positive.
- emilecantin 5y agoIt really depends on your electricity prices. For example, here in Québec (where electricity if very cheap) we don't really see solar panels, but cross over to Ontario and you'll see fields of them. The solar panels I see around here are mostly off-grid applications (boats, RVs, roadside signs).
- iso1210 5y agoThe article is in the Netherlands. Amsterdam is 52N, which is further north than the US (aside from Alaska obv.), indeed there are parts of Alaska that are further south.
- irrational 5y agoI live in the Pacific Northwest where it is cloudy for the majority of the year. In our last house we had panels installed. The amount of money we paid each month toward paying down the loan for the panels was less than what we had been paying each month for electricity prior to the panels being installed. About $50 less per month. Where we live, any excess energy is fed back into the grid and counted as a credit the rolls over year to year. We generated enough electricity to cover our needs, even during the cloudiest/rainiest months. We never had an electric bill more than the required $12 hookup to the grid fee.
- iso1210 5y agoHow many panels, and how many kWh/year were you generating?
- technotarek 5y agoSolar generally pays off if your state/municipality offers SRECs and you get the Federal tax credit. In some places, like Washington DC, it goes as far being lucrative fast. My entire system will be paid off in under 5 years. After that, no electricity bills plus SREC income for another 10+ years.
- newsclues 5y agoIf economic feasibility is based on government incentives (unsustainable) for solar, and perhaps electric cars, is the big green transition that is currently being pushed ever going to be sustainable?
- stormbrew 5y agoI mean, it's not like there's no government incentives on the other side. I'm pretty sure government spending on ghg-emitting energy sources (especially when you take all the externalities into account) are quite a lot more than the rather piddling amount being spent on renewals by comparison.
- avianlyric 5y agoLarge scale solar has substantially better economics that distributed solar. The economies of scale should be pretty obvious. But even distributed solar has a positive ROI, it’s just a long pay off period (20 years etc) without government incentives. But there are plenty of investments out there with lower ROI and longer payoffs that people still invest in. So it’s all economically feasible and has been for almost a decade (which is why we’re seeing so much solar and wind deployment at the moment). Government incentives just accelerate a trend that was going to happen regardless.
- jandrese 5y agoThe downside of Utility Scale solar installations is that my utility provider has zero interest in creating them. Rooftop solar is something I can do that's more effective than creating an online petition to convince my local utility to pursue solar.
- turtlebits 5y agoWhile an interesting experiment, trying to calculate ROI on an a small/inefficient system isn't a very useful metric. - You can get panels for USD $0.38/watt (vs 0.81 in the article), or used for 1/2 that. - Non optimal angle, no mention of what direction the balcony is facing - Standard grid tie systems use microinverters
- ozim 5y agoIt is useful for me. I have a flat and a balcony, it would not be possible for me to have anything bigger than author. I don't have to run such an experiment and I already see that any "backup power" shizzle I would buy on amazon would be loss of money. Better get small fuel generator for any blackouts that can happen.
- petre 5y agoWell, apartment buildings roofs are empty and only collect heat in the summer. Why install solar panels on a balcony?
- AnonymousPlanet 5y agoBecause most people don't own the apartment building they live in.
- irrational 5y ago>the panels are illuminated by the sun at different angles, and the maximum possible angle occurs only once a day What would it take to put these on motors that follow the sun? How much of the energy being generated by the panels would be eaten up by the motors? Would it be a net benefit to have the panels being at the maximum possible angle throughout a greater part of the day, even if part of the energy is having to drive motors?
- castratikron 5y agoAlso, for the cost of adding motors, would the money be better spent on buying more fixed solar panels instead?
- nosequel 5y agoMost big installs have motors. The motors don't take much power to slowly move the panels through the day. The downside is the extra expense of the motors and setup.
- driverdan 5y agoUnless you have very limited space it's more cost effective and much easier to maintain to have more fixed panels.
- jandrese 5y agoMotor mounts don't generally work for rooftop unless you have a flat roof like a commercial/industrial install. They're also more failure prone so in most cases it's easier to just install more panels. Even ground mounts are generally not motorized for home installs.
- louwrentius 5y agoVery cool project! Very similar to mine and I’m also in The Netherlands, I’m using the exact same solar panel stands. I also have the same issue with only getting sun past 16:00 on my balcony so in the winter, the yield is very low. I run my blog on solar + batteries, I don’t deliver power to the grid. On the contrary, I recharge the batteries from the grid in the winter. [0]: https://louwrentius.com/this-blog-is-now-running-on-solar-power.html https://louwrentius.com/this-blog-is-now-running-on-solar-po...
- choeger 5y ago110kWh in one year from 320W is quite bad. One would at least expect 250kWh normally, even more under ideal circumstances. So a better setup can easily half the time until break even. Also, the inverter needs to be scaled to the panels, obviously. If your inverter can do xW, your panels should at least do xW (or more with east/west orientation), or you effectively lose money. So a balcony installation is obviously not the best approach, but one has to wonder about a rooftop installation. What if every apartment would get some part of the roof allocated for private solar? It stands to reason that such an installation could pay for itself in 10 years or less.
- frankus 5y agoI live around 49°N and get an average of ~3 hours of rated output per day over the course of the year. OP's is closer to 1 hour per day. My array does have a clear view of the southern sky, and the angle is supposedly ideal for a fixed array at my latitude. And our longest days tend to also be our sunniest, but it looks like rooftop is much better than balcony, where it's feasible. (Interesting aside: everywhere on earth (to a first order approximation) gets the same number of hours of daylight over the course of a year. Thus the biggest downside of a higher latitude solar installation is that the sun is passing through more atmosphere on its way to your panel).
- jstsch 5y agoAs an experiment I installed a set of the cheapest panels and inverter on my garage last year. 1500 euros for about 2000 watt peak. The mounting materials were a bit more than a third of that. Also paid about 300 euros for the installation. So 1800 euros all-in. Surprisingly, the system is performing quite well, delivering those 2000 watts reliably in the hours around noon, but also working quite well in more cloudy conditions. Bottom line: for around 1 euro per watt you can easily install solar (without subsidies), so as far as I’m concerned it’s a no brainer if you have the space.
- mrfusion 5y agoDid you tie this into the grid? Any permit problems?
- jstsch 5y agoYes, tied to the grid. Simply hooked up to a dedicated breaker circuit. This is in The Netherlands, which means you don’t need a permit to install or connect solar. Practically everyone here has a meter which records power usage and return. Currently, what you return is subtracted from your usage (yearly cumulatives) as an incentive to install domestic solar, although that arrangement will probably be phased out step-by-step after 2023.
- jandrese 5y ago> Practically everyone here has a meter which records power usage and return. Be aware that this is not common in the rest of the world. Most meters are non-directional, which means if you hook a solar panel up to it and then produce extra power, the power company will read it as if you consumed that power from the grid. Effectively you pay the power company for every extra watt generated. Part of the solar install involves calling up the power company to have them come out and swap the meter. Requirements to install Solar vary by community, state, and nation. It even matters where you install the panels. Ground mount and non-inhabited structures (sheds) and often more loosely regulated than rooftop arrays. Even if you are planning to do it yourself it is worth it to call a local installer and discuss the process and local laws. You may need to get permission from the HOA, town, county, power company, state, and even federal government depending on where you live.
- roboben 5y agoMy parents have solar panels on their house since 2007. So if anyone is interested in long term data from central europe (Thuringia), take a a look here: https://www.graefenroda-solar.de/ https://www.graefenroda-solar.de/
- mrfusion 5y agoI wonder why the payback period is so terrible? We always hear about the price of panels coming down but 23 years is crazy.
- stinos 5y agoIn this particular case I think the main factor is purely where the panels are placed and their rather steep angle. Normal paybacks for rooftop are often half of that, if not better.
- caseysoftware 5y agoI just got a 19.98 kWh array (20kWh is the limit) and it cost a bunch but due to the local net billing, we're going to be able to sell back enough that it will wipe out our bill plus some most months.* Specifically, for December, we generated enough to pay the entire bill and create a $70 credit on January's bill. We can't project a trend from a single month but I'm optimistic. * ymmv - Our rooftop is southwest-facing with zero obstructions and we've applied a number of energy-saving tactics inside. Also.. fun side thing on timing. We signed the contract in June. They did the site survey in July. The cells+batteries took 8 weeks for delivery (normally 2-4 weeks) and install has taken forever. Talking with the crew recently, the stated delivery time is 12+ weeks but they're seeing almost 18 weeks. It's a bad time to do this at scale.
- stevenhubertron 5y agoIf I am reading this right (and I am not an expert at all), if wanted to subsidize my current electric bill I could just buy a few solar panels and a grid tie inverter that I just plug into any random outlet and as long as my house consumes more energy than the panels provide and I don't exceed the amperage on the breaker I can effectively do this that simply? (even if the ROI doesn't make sense?)
- Syonyk 5y agoIt depends entirely on where you live. In the United States, the answer is a very clear "No" almost everywhere - those plug in inverters aren't permitted under NEC. Power companies generally require you to have interconnect agreements for any amount of self generation that could interact with the grid (off grid system, have at it, it touches the house wiring, you need to talk to them). The problem with plugging that sort of thing into a random outlet is that now you've violated the assumptions on the circuit protection. If you have a string of outlets, protected at 20A at the panel, then nothing plugged into any one outlet can pull more than 20A sustained (or the breaker will pop), and the wiring will never see more than 20A sustained. If you plug in another source at the far end of that circuit, outlets in the middle and branches off the main wiring run could be seeing 30A without popping a breaker - and that's a fire hazard. A 20A outlet won't pass 30A forever, and wiring rated for 20A can overheat at 30A sustained. In some other countries, you can install some amount of solar and backfeed it like that, but I'm not familiar with those regulations, not living there.
- stevenhubertron 5y agoThank you for the clarity here.. I thought there was more to the story than this article made it seem.
- mindslight 5y ago> the answer is a very clear "No" almost everywhere - those plug in inverters aren't permitted under NEC Of course plug in inverters are not permitted under the NEC, just as kitchen appliances aren't permitted under the NEC, nor are the power lines outside your house permitted under the NEC. The NEC applies to premises wiring, which none of those things are. Plug in devices sold on the consumer market are regulated by UL/ETL/etc, and the power grid is designed by power company engineers working to some other standard. If you look at your service entrance you'll see the wires coming from your house are nice and thick as dictated by the NEC, but connected to a smaller aerial feeder that doesn't meet the sizing requirements of the NEC. Your power company might have some private contractual prohibitions here and you may be opening yourself up to liability from the results of your actions - similar to them getting perturbed if you use a "suicide plug" to power your home from a generator. But it's not generally a priori illegal like you're making it out to be. (Your point about overloading branch circuit wiring is very important though. I'd be more worried about feeding in between the panel and a large load, thereby putting extra current into the intermediate wiring.)
- speransky 5y agoIn run 15 kw solar array on the roof and 5kw over pool, in addition to plenty of daily energy and good grid buyback prices I have nice view from a drone :) also have some monitoring based on grafana and mqtt, both my invertors have proprietary protocols and it was fun to hack them to get data. I think every roof should have pv panels with grid tie connection, so many photons are missed :)
- supernova87a 5y agoOh my god, I have to caution people that the negligible amount of safety information contained in this article is borderline irresponsible. The permitting and regulation regarding feeding energy into the grid is completely underrepresented in this article. If you're thinking about it, you have to seriously read up on the requirements. If anyone knows the author, I would strongly request that he put more cautionary information if he doesn't want to be responsible for some majorly dumb potential consequences. Although the author hints at it, "So, it makes sense to ask the professional advisor first, who knows the local laws and prices, the final results can vary." -- this still makes it sound like it's up to you to DIY it after asking someone for advice on prices(?!). It is not. Tying your solar panels to the grid, at least in the US, requires permits, safety approvals, etc. You can get fined / sued if you're found to be directly connecting solar panels to the grid without having gotten it approved and reviewed. Not just for paperwork and tariff reasons, but because if you generate electricity back into the grid, and they need to shut the distribution line down and perform maintenance, you could electrocute someone. Turning your house main breaker off and running your electronics off solar as an experiment is one thing. Suggesting that going from this hacker setup to sending electricity back to the grid is a whole different level and requires a professional electrician.
- rini17 5y agoThe grid-tie inverter will automatically shut down if there's no external AC supply, that's a standard feature. Also, european legal system is much less prone to judge anyone liable for random stuff they post somewhere just because it can indirectly lead to injury.
- MaKey 5y agoIn some countries you can just connect a small solar installation to a power outlet if you stay at or under a certain wattage (e. g. 600W for Switzerland and Germany). So your reaction is overblown for these cases.
- mindslight 5y ago> Tying your solar panels to the grid, at least in the US, requires permits, safety approvals, etc Maybe your state has specific permits required for solar, the possibility of backfeeding power, or something else of the sort, but I'd say that's more of an exception than the general rule. Nothing here rises to the level of needing an electrical permit (there is no permanent/structure wiring being done) nor building permit (the panels are small and easily movable). Assuming competent wiring and using a receptacle on a dedicated circuit, the biggest safety issue I'd worry about here is the panels being blown off the balcony and falling onto someone below.
- 1970-01-01 5y agoThere's a reason the term 'solar farm' was coined. You're much better off growing tomatoes on your balcony, as balcony-scale solar takes decades to break even. And you won't get to consume anything of higher quality while doing it.
- ketzo 5y agoSince I'm not seeing much comment on the post itself: This was a fun, interesting read. I appreciated the straightforward, concise style of writing. Exactly the kind of content that I love on HN. Thanks!
- kibwen 5y agoNote that this takes place in the Netherlands, which is quite far north globally speaking (~52° N), which has a major impact on solar potential. For reference, the Canadian-US border is at 45° N, so everywhere in the US outside of Alaska will have larger solar potential (the average US center of population is ~37° N, the same latitude as Athens, Greece).
- fulafel 5y agoIn northern places you get the long days in the summer, it's surprisingly good: https://pages.mtu.edu/~raman/SilverI/MiTEP_ESI-2/Solar_energy_and_latitude.html https://pages.mtu.edu/~raman/SilverI/MiTEP_ESI-2/Solar_energ... - nice fit for eg cooling systems.
- ypeterholmes 5y agoSo basically the tech is still a few years away from being cost effective and user friendly.
- ctime 5y agoSolar safety experts who are upset, please note: * The author lives in .nl which specifically allows this type of ad-hoc residential solar (which is probably why he hasn't paid lawyers to provide fine print for his blog post) * The author is using a grid-tie inverter which by definition will not function if the utility is not providing current. There is very, very little risk to anyone including himself at the wattages and voltages he is working with.
- pettycashstash2 5y agoOk so curious how do you ensure that when power goes out that your feed does not cause injuries to power company workers. From my basic understanding, there needs to be an automated switch that detects when power goes out and turns off the solar power. How do you accomplish this.
- DmitryElj 5y agoYes, it is implemented in the grid invertor. Actually a generation should be synchronised with a grid phase, so it is not working without grid voltage at all.
- tiku 5y agoAre you not scared for gusts of wind that will send the panels through your windows? The Netherlands has some rough storms.